Female and male patients diagnosed as schizophrenia by DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) criteria; Age between 18-45 years; Patients who started atypical antipsychotic drug treatment or patients who switched from the previous conventional or atypical antipsychotic treatment to another atypical antipsychotic drug treatment by the decision of their physicians in psychiatry clinics in state and university hospitals.